OMAPDSS: HDMI: init output earlier

Move hdmi driver's output initialization a bit earlier, so that it
happens before hdmi panel init. In the future the hdmi panel will depend
on the output being ready.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Archit Taneja <archit@ti.com>